The disclosure relates to a steplessly adjustable hydraulic insert valve in accordance with the description below.
It is known that proportional directional valves which permit a stepless change in a hydraulic volumetric flow are used in numerous hydraulic applications. For example, proportional directional valves of this type can be used in hydraulic control plate valves for tractors and mobile work implements. One example of a valve of this type is apparent from DE 10 2008 013 270 A1 in the form of a 4/3-way insert valve which makes four hydraulic connectors and three valve positions possible. The electromagnetically actuable directional insert valve which is described therein is provided for being installed into a receiving bore or a stepped bore. It is disadvantageous that a proportional directional valve of this type is structurally complicated and therefore has to be manufactured expensively.
A proportional valve is apparent from EP 1 420 321 A2 which has a completely different connector configuration from the above-described directional insert valve which is known from DE 10 2008 013 A1. It has a housing with a first and a second working connector, an inflow connector and a return connector. A valve slide is received axially displaceably in the housing and is held in an axial center position by at least one spring. The valve slide can be adjusted out of the center position in two opposed axial directions by means of a magnet. Away from the center position, furthermore, in each case one working connector is connected fluidically to the return connector, the other working connector being pressure-controlled. It is disadvantageous that a proportional valve of this type is structurally complicated and therefore of expensive configuration. It has proven disadvantageous in practice that a valve of this type requires a relatively large amount of installation space.
A further example of a proportional valve is described in U.S. Pat. No. 5,249,603 A. It is also disadvantageous here that the described valve is of structurally complicated construction and requires a relatively large amount of installation space.
It is therefore the object of the disclosure to provide a space-saving insert valve using means which are structurally as simple as possible, with the option of hydraulic pressure control.
This object is achieved by way of a hydraulic insert valve having the features described below.
Advantageous developments of the disclosure are specified in the description below.